Method of making naf or naf/aif3involving the reaction of sodium sulfate with fluosilicic acid
Abstract
Abstract A SODIUM FLUORIDE-ALUMINUM FLUORIDE DOUBLE SALT, SUCH AS CHIOLITE, OF HIGH PURITY AND VIRTUALLY FREE FROM CAO AND P2O5 CONTAMINATION, IS PREPARED FROM IMPURE FLUOSILICIC ACID CONTAINING THESE IMPURITIES, SUCH AS THE BYPRODUCT FROM THE MANUFACTURE OF PHOSPHATES FROM PHOSPHATE ROCK, BY TREATING A PORTION OF THE FLUOSILICIC ACID WITH A REACTIVE ALUMINOUS MATERIAL TO CONVERT IT COMPLETELY TO ALF3, AND SEPARATING THE PRECIPITATED CAO, P2O5, AND SILICA, REACTING A SECOND PORTION OF THE FLUOSILICIC ACID WITH SODIUM SULFATE TO FORM SODIUM FLUOSILICATE SUBSTANTIALLY FREE OF CAO AND P2O5 DECOMPOSING THE FLUOSILICATE TO SODIUM FLUORIDE; ADMIXING AQUEOUS SOLUTIONS OF THE ALF3 AND NAF AT ABOUT 140*F.-190*F. WHILE MAINTAINING THE PH BETWEEN ABOUT 3.0 AND 6.8 TO KEEP SIO2 IN SOLUTION, AND RECOVERING THE PRECIPITATED DOUBLE SALT.
Inventors
- 👤 M Harrison
- 👤 D Vancil
Bibliographic Details
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